One more and I’m done...
“(1) Grounding, such as using a grounding electrode conductor (GEC) to connect an electrical panel to a driven ground rod, accomplishes two things:
I. It builds an equipotential plane between the metal cased service equipment and the earth, which reduces the potential for electric shock were someone to touch the earth and an energized metal enclosure of the service (short-to-ground occurring on the service enclosure) at the same time. This reduction in potential for electric shock is due to reduced voltage gradient. Voltage gradient and equipotential planes are a different topic, however, and require extensive discussion. So just remember this simple fact about connecting a metal enclosure (such as a panel box) from the electrical service to the earth: In the event of a short circuit (short-to-ground condition on a branch circuit) the connection to earth will not move current fast enough to trip a circuit breaker or fuse. Yes, that’s right. This “grounding” path established by attaching a grounding electrode conductor (GEC) from the metal cased electrical panel where bare and green equipment grounds terminate, to the earth of soil and rock below, is insufficient for tripping a breaker or fuse during a fault condition. The earth has too much resistance, and electrical current simply can’t flow fast enough to exceed the OCPD trip threshold, most of the time.
II. It diverts lightning strikes so they don’t crawl back up the service drop and into the utility company’s transformer – causing damage. Instead the lightning is diverted to earth.
We must remember: it is the connection between the equipment grounding conductors in the branch circuits, to the neutral conductor from the utility company (by way of the main bonding jumper – MBJ) that trips a circuit breaker when there is a fault. The service neutral from the utility company is the perfect “ground”. It is terminated at the “zero” point in the utility company’s transformer with zero resistance, and that is the point to which all current flowing on the premises is trying to get back to. That “zero” point located within the utility company equipment is intentionally connected to the earth, that is the only reason the earth acts as a ground for a hot wire from the utility company.”
Drive a damned rod.
Want a story how I learned about grounding and bonding from and electrician?
Parents owned a house built in the late late 1800’s. Not in ground in the whole place.
Had a freezer on the front porch (yup... that family) that would knock the shit out of ya. Kept us kids from getting too many freezer pops out. Lol.
Dad called in sparky, and he ran a wire from the freezer (it only had a 2 wire plug, again no ground) to the ground rod for the lightening rods on the roof.
A ground is a ground is a ground.
So, the freezer obviously had a neutral. So why did we get shocked?
No ground.
2 weeks later the fuse in the panel blew. Dad got to messing around found a wire rubbed agains a bracket under the freezer. Little electrical tape and all good.
So, take it for what’s it worth. Bonding is making sure every metal thing is connected to every other metal thing.
Grounding (and yes, you do bond all grounds together eventually) is a safety circuit to earth.
. I’m out. Thanks and I wish you luck figuring out where the shock came from.
Sent from my iPhone using Tapatalk